I once panicked and slammed on ONLY the front brake, and I flipped the bike forwards and nearly landed on my head (I'm at 230 lbs). Won't make that mistake again -- always use the rear brake as well.
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Roy TinkerOct 23 '11 at 3:44

1

Another easy way to flip over is to hit an obstacle. I have gone twice over the bars, and not one time because of front brake. Actually the reason was that my brakes have always been shitty and I couldn't decelerate enough.
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VoracAug 30 '13 at 9:54

Yeah, I've only gone over the bars once as an adult, and it's because I veered into a ditch. When I hit the bottom of the ditch, I had nowhere to go but over the bars. Luckily no harm was done to me or my bike. Hitting an obstacle which stops you while going downhill is probably the most common way of going over the bars.
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KibbeeAug 30 '13 at 12:30

14 Answers
14

It's more dangerous as a kid to flip over your bars because there is much less weight preventing the bike from pivoting around your front wheel when you use your front brake.

The danger still exists as an adult, but using the front brake definitely improves braking performance. If you don't slam the brake there shouldn't be any problems. Additionally you might want to keep your weight on the back of the bike while braking downhill.

Sheldon Brown covers the topic of braking, you might want to give it a read.

TL;DR: use the rear brake any time there's a high risk of skidding the front tire (e.g., on gravel, ice/snow, or front wheel is off the ground). Use your arms to brace against the force of deceleration, and you'll be fine.
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Stephen TousetOct 20 '11 at 4:06

2

On gravel, ice and snow I am also likely to skid the rear wheel. Cycle more slowly in these conditions so that you can control your braking with both brakes without skidding either wheel.
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Sam MeldrumOct 20 '11 at 8:19

This comes under the category of things taught to children which simplify the whole truth in order to facilitate learning and keep them safe. Late on they will be ready to learn how to use the front brake effectively.

When children are learning to ride, they are learning lots of new skills. Balance, pedalling and braking. They don't need to apply a lot of braking force as generally they are travelling slowly - whilst still learning - and also have lower mass - than most adults. So, for safety's sake and to simplify the learning they are taught to apply rear brake first, and front brake later to reduce the likelihood of going over the handlebars. In the conditions children are learning in - generally not wet slippy roads - the risk of skidding or fishtailing from applying the rear brake first is lower than the risk of going over the handlebars and the consequences are likely to be lower impact.

Once you have learnt the balance and pedalling and can ride the bike reasonably well. You can move on to more advanced skills to become a really competent rider. One of those is how to stop more quickly when going at speed and with more weight on the bike (i.e. you're bigger). Now the risk of skidding the rear brake, or just not stopping in time due to inadequate braking force applied for the speed and mass is greater and needs to be dealt with. If the front-brake is used properly it can apply much greater braking force, without the risk of skidding associated with the rear brake. The most critical things is to ensure you keep your weight behind the front wheel and not over the top when applying the front-brake. To do this, ensure your weight is toward the back of the bike and that your arms are braced against the handlebars to absorb the force and keep you on the bike.

Basically you just have to get a feel for it, depending on your bike, the brakes, your weight, what you are carrying (eg rear panniers), and the road conditions (loose surface, wet, downhill etc).

The two main things to beware of when front braking are:
1. Not going over the bars.
2. Not front braking through corners.

You can get away with the second one when traction is good, but you only need a little gravel, a little oil (middle of lane at lights is full of oil) that can cause your front wheel to lose traction under front braking. So #2 still holds! Avoid it! You should brake before corners.

When braking in a straight line you should use your front brake mostly, as it is your most effective brake, being wary of going over the bars of course.

For slow manouvering, or one handed riding (sometimes you have to indicate whilst cornering), or if you have to brake whilst cornering, use the back brake smoothly.

I have alleged the opposite in my answer: that when braking through corners, only use the front brake.
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ChrisWAug 30 '13 at 12:06

@ChrisW Motorcycles are similar to bicycles in braking dynamics. A motorcycle safety course will teach you that the front brake is the most effective brake to stop you in a straight line but the most dangerous brake whilst cornering. A skilled rider may be able to control rear wheel slide in corners or on loose surfaces but once the front starts to slide no amount of skill will save you. Controlling speed before corners is the most critical factor though. It can save your life. In Australia around 50% of motorcycle fatalities are simply due to going too fast into a corner.
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Jason SAug 31 '13 at 3:46

If you ride only paved surfaces, there is not much problem to use front brake, I think.

The main problem (from my extensive off-road background) is braking on curves or slippery terrain, where you should take a bit of care not to block your front wheel and fall from the bike.

I am not saying the front wheel should not be used on curves, or on unpaved terrain, only that extra care should be taken to modulate front and rear brake forces so as not to block and slip the wheels (unless, of course, you want to skid the rear wheel on purpose to correct your trajectory, which is a very useful menoeuver sometimes).

Also, when you go down a curb, specially when going down a slope (for example, going from sidewalk to street), brake modulation and demodulation might be useful too: when each wheel is "in the air" between the two different height surfaces, the brake on that wheel should be quickly released, and just AFTER that wheel hits the ground it should be used again. It helps not to tip over the front wheel, and not to skid rear wheel (I care about my tires).

Hope it helps!

PS: and just to answer your last question, FOR SURE you should use your front brake abundantly! It is the front brake that saves lives (yours and others')

It is remarkably easy to flip over the front wheel (I have done this as a child and as an adult) but far more commonly what happens is that if there is a slight turn on the handlebars and the surface is at all slippy the front wheel will fire out sideways extremely rapidly and you find your face at ground level!

I learned a lot of my control on a bicycle from motorcycling as a child, and a lot of the teaching is directly appropriate:

The way use of the front brake is taught in motorcycling is that you
use the back brake a lot, and only ever use the front brake when
braking in a straight line, and slowly increase pressure on the
brake as the front wheel loads up (so you get more grip due to the
additional load rather than braking traction.) In reality you can use
light front braking any time you have reasonable traction, but the
recommendation is to avoid it becoming a habit as in an emergency
situation you might just grab the brake lever!

Losing traction on the front wheel is generally unrecoverable on a bicycle, whereas losing traction on the back wheel doesn't even really impact your ability to steer so it is always preferable to use the back brake more.

What may be good advice on a motorbike really isn't on a bicycle. The front brake is far more powerful than the rear on a bike and knowing how to use it a vital skill. Not only does over use of the back brake increase stopping distances it also cuts up the trails when riding off road as people inevitably skid.
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JacksonOct 20 '11 at 14:01

1

@Jackson - the front brake being far more powerful is exactly the same problem on a motorbike. The only difference is around mass and velocity, generally. I agree knowing how to use it is vital, which is why I have explicitly discussed its usage in my answer.
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Rory AlsopOct 20 '11 at 14:03

1

In NSW, Australia, to get a motorcycle license you have to do a course. They tell you that for an emergency stop you should brake in a straight line and 70% on the front and 30% on the rear brake. You have to do an emergency stop as part of the test to get your license. Depending on the brakes on your bike, it is easy to fail the test if you're not hard enough on the front brake. You would fail if you only used the rear. You have to do slow manouvering as part of the test in which case you can use only the rear. They do say though that only use the front brake in a straight line.
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Jason SOct 21 '11 at 6:07

1

@Jason, and increasing the front brake as the weight loads up on the front is essential, as you need the weight onto the front wheel before you can really use it.
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Rory AlsopOct 21 '11 at 11:37

As with the above, I ride MTB like I ride a motorcycle, and that's to the rule of hard braking in straight lines, applying greater ratio of braking to the front wheel, and controlling risk of locking up through feathering. Also exactly like a motorbike, you can control cornering through use of the back brake alone, where controlled forward momentum will help your slow ride abilities (road bikes in traffic, MTB's through risky log crossings etc).
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ddriMay 6 '12 at 13:51

In 30 years of riding in hilly cities and in the mountains, I use both brakes.

As for the front brake... I don't jam on it heading downhill. Also, it's most always the secondary brake when negotiating tricky downhill curves.

This is the type of thing that one has to develop a "feel" for. At times, I may be on the front at 20% and the rear at 80%. Or maybe 50/50 in other situations. In emergency braking situations, sometimes my butt is actually behind the seat and over the back wheel.

Suggestion... find a moderate, low traffic hill and practice, so that you understand how braking feels when heading downhill. Practice shifting your weight to the rear of the bike; and practice with varying degrees of pressure on each brake. After a few jaunts up and down a hill, you'll have a good idea.

Anecdotally, A while back, I had a rear brake cable that broke on a long descent out of the mountains... basically, I had to use the front brake only to slow down and stop. Probably one of my scariest situations.

Certainly not Alpine. But it may be 3-4 miles of steady downhill.
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Daniel R HicksOct 22 '11 at 3:02

@Daniel R Hicks, doesn't that provide less control than using both brakes? That is, see my answer below.
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VoracAug 30 '13 at 9:51

@Vorac - When I'm just controlling my speed on a long (highway) downhill, there's no loss of "control" using one brake at a time. The other brake is there if needed.
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Daniel R HicksAug 30 '13 at 11:11

I've seen a video of a guy going head-over while braking. It happens amazingly fast. (Similar, BTW, to how rapidly a farm tractor will flip over backwards if you tow by wrapping a rope or chain around the rear axle.)

Going head over this way is pretty much inevitable if the front brakes lock -- weight transfers to the front wheel, multiplying its traction, so the front wheel simply cannot skid (on a dry surface). And, as I said, it happens too fast for you to react.

But unless your brakes are exceptionally "grabby" this doesn't happen in anything short of a panic stop -- ordinary downhill braking to control your speed is not a hazard.

I've seen it recommended that you apply about equal force to both brakes, and when you sense the rear wheel skidding, let up on both (since the rear wheel WILL skid). I have no idea how hard this is to do in practice -- I'm not so aggressive a rider that I want/need to find out.

I have no idea how hard this is to do in practice Some places have as a legal requirement that your bike must have sufficiently-effective braking that you can skid the back the wheel. You could try it on an empty street, using only the back brake. An argument for trying it is that you may need to emergency-stop some time.
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ChrisWAug 30 '13 at 12:13

Yes you can most definitely flip over if you press your front brake too hard. But also it's the most powerful brake as when you brake, your body weight will push/pivot onto the front wheel causing it to transfer most of the force from/to the ground.

The angle of your front fork, a steep angle will cause you to flip over easier compared to a downhill bike where the fork almost points straight forward.

Is your front fork suspended. This in combination with a not so steep fork angle will allow you to notice easier where the limit goes as the suspension will usually contract fully before you start pivoting.

If I need to brake I want to brake. The front brake is far more effective than the rear. Thus, I use the front brake.

I have never come close to going over the bars due to front braking. Going downhill, hitting items combined with braking will possibly get you in that situation.

Mostly this is a function of riding, getting comfortable on the bike and being prepared.

I think the admonition for kids (or anyone) 'not to use the front brake" is stupid and dangerous. It makes people think they should not use it and in cases where full braking power is needed they either are not able to do so or reluctant and get into trouble.

Other good answers have not mentioned group riding. If you are riding in a pace line, club group, charity ride, etc., you should not use your front brake except in emergencies. In short, any time you have someone riding behind you, you need to slow gradually whenever possible and your front brake slows you much more quickly.

Since I do a lot of group riding, I wear my rear brake pads out first, which is not typical.

The basic tactic for using your front brake is to shift your weight backward on your seat as you grab the brake. It takes a lot of experience to make this habit automatic, but it will keep you from flipping even in emergencies. You may still have the rear wheel hop if you grab very hard but you won't go over the handlebars.

When the front wheel is bouncing up-and-down-to-the-rivers-of-Babylon, engaging the front brake is

ineffective at decelerating

reducing traction and increasing chance of slipping.

This is the ideal case, of course. Use the front brake, but modulate it. When in the above-mentioned conditions just have in mind that the above results could happen from too much pressure on the front brake (basically if stopping only with the front brake).

The practical advice: at rough terrain, consider shifting the breaking balance a little to the back wheel (for example 60% front 40% back).

I have hydraulic disk brakes: which feel like they could stop a truck; and I ride on paved surfaces.

If I ever squeezed the front brake as hard as I could, I have no doubt that I'd flip.

When I squeeze both brakes semi-hard, e.g. for an emergency stop, then the back wheel starts to fish-tail. The back wheel will begin to skid before the front one ever will: because weight is thrown forward when braking, so there's more 'weight' on the front wheel than on the back, and friction or grip is proportional to downward force. The back wheel's beginning to skid is therefore a warning that too much weight is coming off the rear wheel, and so a warning not to be braking quite so hard.

The back wheel's fishtailing slightly isn't too bad, when coming to a straight-line emergency stop.

Once however I used both brakes, when going around a bend: and the back wheel slid out from under me, and I went down.

So now when I am braking while going round a corner, I only use the front brake: it's always less likely to skid than the back wheel is, and I find it hard to imagine it ever skidding at all (in the extreme it would be IMO more likely to flip me over the handlebars than to skid, except when the road surface is compromised by ice or dirt).

Braking only with the front brake in turns is quite a risky thing to do. Of course it is best to not brake at all while cornering but if you can't prevent it, you should do it with your rear brake. If your rear wheel skids or slips this situation is easily controllable – front wheel losing traction is not. And in sharp turns where you would need nearly all your traction to keep your wheel on track, additional braking forces on the front wheel may make the difference between rolling and skidding.
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Benedikt BauerAug 30 '13 at 12:07

@BenediktBauer I understand your argument. My theory is that skidding the back wheel is not controllable while cornering (i.e. when you are already leaning over and with your feet clipped to the pedals), and that the front wheel (although equally uncontrollable if it skids) is much more difficult to skid.
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ChrisWAug 30 '13 at 12:17

An up-voted comment elsewhere says, "and increasing the front brake as the weight loads up on the front is essential, as you need the weight onto the front wheel before you can really use it" ... which may be true.
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ChrisWAug 30 '13 at 12:25

The problem is that on a turn the dynamics are completely different -- weight transferred to the front also increases the outward thrust on the tire, and if the surface is at all "iffy" the likelihood of front-wheel skid-out greatly increases.
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Daniel R HicksAug 30 '13 at 14:48

From motorcycle to bicycle and even to car, braking through corners is generally not a good idea. Braking should be done before cornering. A motorcycle safety course will teach you not to front brake in corners and to brake before corners (around 50% of motorcyle fatalities in Australia are simply going too fast in corners). I'd be concerned for your safety and others with the advice to use the front brake in corners. A rider may be able to control a rear wheel skid (and back off the brake), but no amount of skill will save you if your front wheel loses traction whilst cornering.
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Jason SAug 31 '13 at 3:34

Actually you can always use front brake but you should never lock your front wheel if handlebar is not in straight position. You definitely do not want front wheel skidding because you cannot control it. Plus this applies a twisting force to handlebar and can pull out of your hands.

FYI: despite the other answers said, inertia pushes you from the saddle toward the handlebar when you decelerate whichever brake you use, front, rear or both. One could fly over the handlebar because decelerating too hard, regardless of brake used.

Also, adult have more mass than kid, and therefore have more chance to fly over due high centre of mass of bicycle-cyclist.

You should never lock your front wheel, period. If you do, you WILL go head-over, because the front wheel basically can't skid when on dry pavement. And it's pretty well impossible to be thrown over the handlebar using only the rear brake, unless you're really being stupid -- the rear wheel will skid well before enough force is generated to throw you over.
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Daniel R HicksOct 22 '11 at 3:00

@Daniel R Hicks, more like comma. Locked front wheel slips, and if it slips right in the direction of bicycle movement and grips held firmly - bicycle stops. Your impression what braking by rear brake is milder does not make any sense and actually causes by worn out shoes. Physics is the same.
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Premature OptimizationOct 22 '11 at 6:16

3

When the front wheel locks, the weight of the rider is transferred to the front wheel. More weight means more traction. On dry pavement with normal tires the physics of the situation (as described by several authorities) is such that the front wheel CANNOT SKID, so a head-over is inevitable. With the rear wheel the physics are exactly opposite -- weight is transferred to the front and the rear wheel is lifted off the ground, until it loses traction and skids.
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Daniel R HicksOct 22 '11 at 11:46